Coolant or cooling systems for motorcycles have been around for many years. One popular method of cooling an internal combustion engine for a motorcycle is liquid cooling. This approach to engine cooling involves the use of a radiator (similar to the radiator on a car) for dissipating heat produced by the engine. A motorcycle radiator uses coolant (i.e., water or a coolant liquid) that circulates constantly between the radiator and the cylinders of the engine during operation, thereby dispersing the engine heat. Another approach to engine cooling takes advantage of the air blowing past the cylinder and cylinder head while in motion to disperse heat. The cylinders on these air cooled motorcycles may include fins (i.e., heat sinks) to aid in the heat dissipation process. Air cooled motorcycles may also be equipped with fans that force air past the cylinder block in the event of sustained stationary periods that may cause over-heating.
One of the main drawbacks of conventional radiator-cooled systems described above is the limited amount of coolant available to cool the motor. Generally, the amount of coolant available to cool the motor is limited to the internal volume or capacity of the cooling system. I.e., the cooling system can only retain as much coolant as the radiator can hold. Another drawback of conventional radiator-cooled systems is the limited amount of surface area of the radiator available to disperse the heat that is garnered by the liquid coolant. Because motorcycles and mopeds have a relatively small overall size, there is a reduced amount of space available for a radiator. This, in turn, limits the amount of surface area available for the radiator to radiate the heat picked up by the liquid coolant. As a result, the cooling capacity of a motorcycle radiator is restricted.
Yet another drawback of conventional radiator-cooled systems is the limited number of systems directed to cooling electric motors. An electric motor generates heat in a different manner, in different locations and in different amounts compared to an internal combustion motor. Consequently, cooling of the electric motor in an electric motorcycle involves needs that are not currently met by conventional radiator-cooled systems for motorcycles. U.S. Pat. Nos. 5,293,089 and 5,859,482 disclose liquid-cooled electric motors but fail to disclose an adequate mechanism for dissipating the heat siphoned from the electric motor. U.S. Pat. Nos. 5,255,733 and 5,531,285 disclose liquid-cooled motors for hybrid vehicles but only in conjunction with a conventional radiator for dissipating heat.
Therefore, a need exists to overcome the problems with the prior art as discussed above, and particularly for a more efficient cooling system for an electric motor of a motorcycle.